APG Begins Modernization of the More Than 75-Year-Old Ennstal Transmission Line

The approximately 73-kilometer transmission line has been in operation since 1949 and plays a key role in ensuring a reliable electricity supply to the Enns Valley and beyond. As part of the project, all 234 towers and their technical components will be upgraded to meet the latest standards. The project covers approximately 56 kilometers in Styria and 17 kilometers in Salzburg.

“With an investment of approximately €240 million, we are modernizing a vital lifeline for the region, doubling its transmission capacity to approximately 1,200 MVA, and laying the foundation for a reliable electricity supply, the integration of additional renewable energy sources, and the sustainable development of the region. A high-capacity, trans-regional electricity infrastructure is a fundamental prerequisite for affordable electricity and, consequently, for an attractive business location,” emphasizes Gerhard Christiner, Spokesperson of the APG Executive Board.

More capacity along the existing route

An important aspect of the project is that the line will be replaced along its existing route. The voltage level will remain unchanged at 220 kilovolts. As part of the modernization, the towers, foundations, conductor cables, grounding systems, and fittings will be modernized or replaced. The existing single conductor cable will be replaced by a double configuration, significantly increasing the line’s transmission capacity. At the same time, corona noise — the characteristic crackling sound sometimes associated with overhead power lines — will be reduced.

“The route will remain unchanged during the modernization. The new towers will be erected at the same locations and will have the same footprint. Depending on the location, they will be up to ten meters higher. This ensures that the high standards for electric and magnetic fields in the vicinity of residential properties will be maintained and, overall, further improved. In addition, the increased clearance height will make it easier for agricultural machinery to pass underneath the line in many places,” explains APG project manager Patrick Rupp.

Main construction work to continue through spring 2028

Preparatory work has been underway since March 2026. This included road construction, bridge reinforcement, and the installation of protective scaffolding and assembly areas. Following the shutdown of the transmission line on July 20, the main construction phase has now begun. For this purpose, the route has been divided into five construction lots, with work progressing in parallel throughout the construction period. The main construction work is scheduled to continue through spring 2028. Full completion, including the restoration of roads and the reclamation of land, is scheduled for fall 2028.

“Since the shutdown began, we have been dismantling the existing line. The first step is to remove the conductor cables, old towers, and foundations. The modernized line will then be constructed at the same locations,” says Rupp, describing the construction process.

An important east-west connection for Austria

The Ennstal transmission line is far more than a regional power supply. As a key component of the APG grid, it connects high-generation regions in eastern Austria with pumped-storage power plants in the west.

“The Ennstal transmission line is a central part of the east-west connection within the APG grid. It enables electricity generated from renewable sources to be transported across Austria to wherever it is needed at any given time. In this way, it makes a significant contribution to the country’s security of supply and to a successful implementation of an affordable energy transition,” says Christiner.

Strong boost for the economy and employment

In addition to its importance for the energy sector, the project will also generate significant economic benefits. According to an Economica study, the approximately €240 million investment will generate around €112 million in gross value added in Austria, with more than €10 million benefiting Styria.

“Around 1,300 jobs will be created during the implementation of the project. This demonstrates that investments in the electricity infrastructure not only strengthen the security of supply but also generate important economic momentum for the regions and for Austria as a whole as a business location,” says Christiner.

About Austrian Power Grid (APG)

As an independent transmission system operator, Austrian Power Grid (APG) is in charge of ensuring the security of the electricity supply in Austria. With our high-performance and digital electricity infrastructure and the use of state-of-the-art technologies, we integrate renewable energies and reduce the dependency on electricity imports, we are the platform for the electricity market, and we provide access to reasonably priced electricity and thus create the basis for Austria as supply-secure and future-oriented industrial and business location and place to live. The APG grid totals a length of about 3,500 km and is operated, maintained, and continuously adapted to the increasing challenges of the electrification of businesses, industry, and society by a team of approximately 1,000 specialists. 67 substations are distributed all over Austria, and the majority are operated remotely from the control center in Vienna. Thanks to our committed employees, Austria had a security of supply of 99.99 percent also in 2025 and thus ranks among the top countries worldwide. Our investments of 680 million euros in 2026 (2025: 595 million euros, 2024: 440 million euros, 2023: 490 million euros) are a motor for the Austrian economy and a crucial factor for achieving Austria’s energy goals. Overall, APG will invest around 9 billion euros in grid expansion and modernization measures by 2035.